Introduction 3 



to him for Identification, or displayed others that he had 

 gathered and on which he was then (i 876-1 882) pub- 

 lishing. 



The Impression was, therefore, almost unwillingly 

 forced in on the writer's mind, now fully forty years ago, 

 that during the great Carboniferous epoch a practically 

 continuous deposit of freshwater strata with typical plant 

 and fish enclosures gave rise to the foundation beds or 

 Calclferous Sandstone series of that system; that then an 

 extensive though not deep submergence of land occurred 

 under the sea, during which the Carboniferous Limestone 

 was formed as a great marine deposit. Even then however 

 occasional elevation for a longer or shorter time permitted 

 the development of a nearby land flora and Invasion again 

 of teeming freshwater fishes In lakes or swamps of that per- 

 iod. These however showed no trace of existence In marine 

 strata. Finally, during deposit of the Coal Measures, 

 freshwater fishes that were very different in type from those 

 of the lower rocks, were met with In Ironstone in shale, 

 or in sandstone strata that alternated with and often shaded 

 into coal beds. 



The mental picture thus gradually formed through a 

 period of fully five years — namely from 1876 to 1881 — 

 seemed antagonistic to the tacit or openly expressed views of 

 many palaeontologists and zoologists. Very slowly through 

 succeeding decades a correct explanation began to dawn, 

 and this was outlined recently In the volume that the 

 present writer has entitled "The Causes and Course of 

 Organic Evolution." Shortly stated, and founding on facts 

 presented In Chapters 11, 12, 14, and 18 of that work, he 

 would claim that all organic life evolved In freshwater 

 and even most primitively in thermal or subthermal areas 

 akin to those of the Yellowstone, the New Zealand, the 

 Austrian, the Icelandic and like regions of to-day. This also 

 took place, he considers, In early proterozoic, protoblotic 

 or archean time. Gradually new and ever more complex 

 forms evolved which continued to Inhabit freshwaters. 

 But from such freshwater environment successive organ- 

 ismal Invasions of the sea first, and of the land at a later 

 period, started the main groups of marine plants and ani- 



